1. Technical Field
The present invention relates to a method of enhancing speech using a variable power budget in order to overcome a partial masking effect due to near-end background noise.
2. Description of the Related Art
When a user is on the phone or listening to music, noise present at a user side directly reaches ears of a user, and thus deteriorates speech quality of the other party while reducing the amplitude of a speech signal felt by the user. Thus, understandability and intelligibility of speech of the other party are deteriorated and it is more difficult for the user to listen to the speech of the other party as the noise increases.
When a power spectrum of ambient noise cannot be controlled despite being able to be estimated, there is proposed a method of enhancing a speech signal reaching a receiver side. A method of simply increasing overall power of speech is not desirable in consideration of frequency characteristics of noise. In addition, although a method of completely masking noise by a signal in each band by amplifying a frequency component of the signal has been proposed, this method has a problem in that an original sound becomes too louder when noise is severe.
Further, a method of enhancing speech by optimizing a speech intelligibility index has been proposed. The speech intelligibility index for each frequency band is determined through several experiments and is designed to allow clear recognition (intelligibility) of a speech signal. Namely, this method allows a receiver exposed to near-end noise to intelligibly listen to speech by maximizing intelligibility of a far-end signal (signal from a sender side). However, since a limited power budget is used in this method, the method has a limit to actual application.